This bioarchaeological study serves to determine whether the socio-political status of a population is reflected in the composition of the looted machay tombs at Hualcayán (1 AD - 1400 AD) in the north-central highlands, Peru. Archaeological studies of Andean mortuary practices reveal much about the social organization of kin-based corporate groups, or ayllus. Ayllus emphasize unity as well as hierarchy and group affiliation determines access to labor, land, water, and other collective assets. Elite ayllus had the responsibility to fulfill certain obligations—including participation in political decision-making and religious rituals. A privileged ayllu interred their deceased in large funerary structures to convey the status of the individuals buried.

The cemetery consists of approximately 90 machay tombs that vary from small semi-circular rooms beneath natural rock crevices to chambers built underneath large boulder outcrops. This study compares the external long bone dimensions between one large and one small machay to test whether the differing tomb sizes reflect disparities in socio-political standing between ayllus. Non-elites with heavy workloads put physiological stress upon their bodies and generally display more robust long bones compared to those partaking in administrative or ritual activities. Measurements documenting a lower midshaft circumference of the tibias and femurs from the large tomb may suggest that privileged ayllus buried group members in the larger machays to express the powerful social position of the deceased. The results of this study demonstrate how skeletal analysis may reflect social differentiation among prehispanic Andean groups.